What's protocol for if you see someone's ccw exposed and they appear unaware that it is?

Saw someone last week and it looked like he had reached up high and the shirt cam down on top of the pistol, exposing it clearly. This was in close proximity to the protesting crowd, which was around the only restaurants in the small town. It was an iwb holster so I assumed it was to be concealed. I said "hey man, check your shirt" and he looked upset with me. I was walking and on the periphery so I didn't present any threat.Just curious if there's a standard practice. via /r/CCW https://ift.tt/3cAz8jB